Duran, Moore and Monzon are the stand outs for me from the original list. Oh, and Ezzard Charles, (Sorry George !). Lots of other great names too. I would give "Old Bones" Joe Brown a mention too.
Sammy Mandell is underrated in general but had a high ring IQ. Great fighter. Ross. You don't get as far as he did- arguably a top ten fighter of all time - with no punch and a non-exceptional level of athleticism nor insane defensive talent (though he was no doubt quick and defensively good) without truly great intelligence and ring generalship. Lou Ambers too, though he was aided by great strength and infighting ability despite lacking other physical tools a bit. I think it counts for more when a fighter lacks any number of truly elite physical aspects but achieves greatness still, being forced to rely purely on a range of tricks, technique, great fundamentals, adaptability, versatility, mental strength, speed of thought, general fighting nous and instinct etc. Most fighters have exceptional physicality though I suppose, in one way or another, be it speed, stamina, strength, power, chin. Ross, who I mentioned, had tremendous stamina and was made of iron.
Not an all time great, but Greg Haugen had a very high ring IQ. He fits into Tin's criteria of being a guy without any special physical attributes who became a top fighter on skill and smarts alone.